Rectifier



v July H3.. s. RUBEN @@79937 RECTIFIER Filed Aug.23, 1950 2 Sheets-Sheev. 1

/r A ,f ATTORNEY My., m s. RUBEN ,mm3

RECTIFIER Filed Aug. 25, 1950 2 Sheets-Sheet 2 i ATTORNEY be Vwoundin Patented July 9, 1935 Application Aufrst 23,'

i"'This inventionrelates` to rectiilers` and par- .ticularly those ofthe gaslled typ l One of theobjects of the invention is to provide a rectifier whichjwill handleilarge current density IAnother object.' ofthe invention is to provide a rectifier which mayl be connecteddirectly to the power line without intervening transformers. j i ,Other objects and :objects relating particularlyv to the construction and assembly of the various 'parts will be apparent as' the description ofithe invention proceeds.. :I f v Y -igThe invention is illustrated in the accompanying .drawings infwhichz' l', 1 Fig. 1 is a front elevatiena'l'view of a half wave rectifier tube embodyingthe invention; {n.Fig'.. 2 is a` plan liview` .of theelementsqof the rectier; shown inl'igflN l xl'ig, 3- is aiside elevationalview of theelements shown irijFig. 1;Y a Fig. 4 is jafcircuit; diagram showing the, means of usingihe: construction of Fig. 1;?

- 'Fig .5 vis, a sectona-lifront view of a-.full'awave rectier embodying theginvention; 1 Fig f6 sfaplan View .lofthe elements of Fig.l L 5; 11 Figv'iis asideviewpfthegelements of Fig. 5; f fFig; 8 .is a circuit diagram 'showing the connections which may be used withthegconstruc- "lg. 9is an enlarged longitudinal sectional view orioneendiof'one of the electron emitting'elements; mi. i' il 1 Referring now morespecifically tothe drawings my improved rectifier hasbeenshown as' comprisingfan` envelope IB ofg glass or other transparent material; mountedlupon theusual Vpress I I which is made integral therewith and which supports the elements-of the device. An` electron emitting element' I2-may be supported at its lower end upon a; support rod I3 which may extend downwardly and maybe sealedlin-.the -press I I and at its upper end by a support rod IB which may be'bent backwar diy-and` downwardly and Yinwardly again and may` also-bes ealeclin` the 'press I l. f The support rodIfl is, of course, spaced from the element I2 which maybe positioned substantially on the axis ptthe envelope IOMif desired:` 'l v Iheelement I2 may comprise a coil I5 (see Fig.

9) of resistancewi-re such' as tungsten,jtantalum,

nihwmev Orithe :like-which: may a coil of relativelysmall diameter. t .'MIIlfier-outer surface ofthe-coilmaybe c :oated with anelectron emitting materials Illwhichy'maybe molybdenum,

l any4 offthe materials knownin the art; andused for that purpose,4 such ast-he oxides ofthealkaline 'saith metals-premixtures taf fany;.o,fthes,efma

2,067,937 RECTIFIERT f PATENT. @Fasce-55:

chelle, NLY., assigner to; k yi liewark, Ns al cor- 1930,'Y saisine. 477,303

terials; The materials may be spread on the surface of 1 the coil in any'desiredmann'er asmby brushing'and then 'allowed to dry forming a hard coatingon thesurface of the'coil. 1" A tubular anode or plate Il may be'positioned around theelement l2 andmay comprise'a pair of cooperating.semi-cylindrical members i8 having radial Yiianges l!)V at the sides thereof `which fare adapted to be placed back to back to form a hollow cylinder with radialiianges extending diamjet rically opposite each otherjasindicated in Fig-12, Theflanges i9 may be provided at their edges with groovesjEil whicht theV support rods Zij; to which the anges may be welded. The support `'rods 2i may extend downwardlvand may be sealed'into the press I i while the upper ends thereofmay be bentrearwardly and downwardly gas, preferably a` monatomic gas, such as neon,

argon; helium, krypton, or Xenon,or mixtures of such gases, and to'give bestresultsmay prefer toshaivea pressure of aboutZOO mm. of mercury.

With the elements mountedonthe 'pressas indicated vand the press sealedinto the envelope the; envelope 'may be connected in a 'mannerwell knownfin the art'to anexhaust 'pumpaandrsan oven placed thereover to raise the temperature' to between'j350 to 4001C. or as high a temperature as the glass willstandwithout softening. vA 'current may be run throughtheelement i2 at thistinie suicientto raise the temperature .thereof to about 600 C.- and this process may be` continued until all'of the' gases and vapors are withdrawn Afrom the envelope whichis evidencedby'the lack of fluorescence when high tension current from an induction coil `is directed against the walls ofthe bulb; Current may then beincreasedthrough the iilament to raise'the temperature thereof to about 800C.` giving it 'a bright red color. This drives outfithe.binderffrom the electron emittingina-V terialand other occluded gaseswhicli` may'be present. The gases v thus drivenoffare withdrawn by the pump and when no more gas is found-in the bulb the oven maybefraised and-the filament may-be heatedfor 'a moment to 'approxi'- mately 1200? C. todrive out any moreg'aseswhicl maybe present, the 'pump 'being'cnnctediall this time to maintain a high vacuum which at this stage should be about .5 of a micron.

The pump may then be shut off and the filament current turned off and a small amount of an inert gas, such as neon at about 1/2 mm. pressure, may be admitted to the bulb and the lament current turned on again and gradually increased. Spots of localized discharge will then appear having a reddish color and will gradually increase and spread until a diffused bluish glow completely fills the bulb. This process appears to activate the electron emitting coating and raise the efficiency thereof and usually takes less than ten minutes to complete. During this time the current on the filament should not be raised too high so that the coating will not be destroyed or thrown off from the filament. If white discharge spots appear on the filament or support rods it is an indication that there are more gases or vapors in the bulb and the bulb should again be exhausted and the process of activation repeated. When the activation is completed the filament temperature may be raised for a moment to about 1400 C. and then the vacuum pump again connected and the bulb pumped out to remove any undesirable gases which may be thrown off during the activation process. The filament circuit may then be disconnected, the pump turned off, and about 50 mm. of neon gas followed by about mm. of argon may be admitted to the bulb. The bulb may then be sealed off and may be ready for use after a small amount of magnesium is flashed to absorb any impurities.

In order to increase the conduction of the gas in the envelope I may desire to add a small amount of metal vapor such as the vapors of mercury, caesium, or rubidium. If a small amount of a salt such as a chloride o f one of these metals vis placed in the container 26 for the magnesium which may be supported o n a wire 21 attached to one of the support rods, as the rod 2l, the magnesium will react with the salt when it is flashed and liberate the free metal which will condense Von the walls of the bulb to be evaporated when the rectifier becomes heated in use.

In Fig. 4 one circuit for using the device is shown diagrammatically. The element I2 is connected to the secondary 28 of a transformer 29, the primary 30 of which may be connected vto a sourceof alternating current. Another secondary winding 3| having one `end connected to one end of the winding 28 may have its other end connected through a load 32 to the anode l1.

When current ows in the primary 3i) of the transformer the element l2 is energized and an ionicdischarge takes place along the surface of the element. This discharge appears like a halo around the element and is confined to the region of the element by the pressure of the gas in the envelope. When the anode has a positive potential due to the direction of the current flowing in the secondary 3l, current will flow between it and the element l2 through the ionic discharge field and when the anode is negative, when the current is reversed in the secondary 3|, the ionic discharge around the element I 2 tends to collapse and no current will fiow between these two. Thus current flows through the load circuit 32 'only in one direction, rectifying the current for 1/2 of the cycle.

If a full wave rectifier is desired the construction shown in Figs. 5 to 8 inclusive may be used. Here an element 33 may be supported uponfsupport rods 34 and 35, the latter connected Vtothe top of the element and being bent backwardly and downwardly where it may be sealed in the press 36. A pair of tubular anodes 31 and 38 both having relatively the same diameter may be positioned around the element 33 concentrically therewith and spaced apart longitudinally as indicated in Fig. 5. The anode 31 may be formed of a single strip of nickel or other metal bent to form a hollow cylinder provided with a flange 39 which may be welded to a support rod 40 sealed in the press 36 and extending upwardly spaced from the element 33 and bent rearwardly above the flange 39 and downwardly again where it may be sealed in a bead 4I attached to the support rod 35. The lower anode 38 may be formed similarly to the anode 31 and provided with a flange 42 which may extend in the opposite direction to the flange 39 and which may be welded to a support rod 43. The rod 43 may extend upwardly beyond the anode 38 and may be bent rearwardly and downwardly where 'it may be sealed into the bead 4I similarly to the support rod 40. In this Vcase'the (element 33 may be formed Vsimilarly to the element l2 as described.

In Fig. 8 a circuit is shown in which the full wave rectifier may be used. The element 33 may be connected across the ends of a secondary 48 of a transformer 49, the primary v50 'of which may be connected across an alternating current source. The anodes 31 and 3B 'may be connected to the ends of another secondary winding 5I and a center tap 52 on the winding 5I may be connected through the load circuit 53 to a center tap 54'on the secondary winding 58.

Alternating currentthrough the primary 50 of the transformer 49 energizes the secondary 4'8 and therefore the element 33 which is caused to emit electrons'and a halo of ionic discharge forms along the element. During one cycle the anode 31 becomes positive and the anode 38 negative due tothe current flowing in the secondary 51 and during the other cycle this condition is reversed. When the anode 39 'is positive vcurrent flows between it and the element 33 while the' negative anode V38 tends Vto collapse the'halo around that part V'of the element. When 'the anode 38 becomes positive and the other negative the condition is reversed so that'dur'ing both cycles of the alternating current 'wave unidirectional current will ow through the load Acircuit 53. It will thus be seen that the -device shown in Figs. 5 to 8 inclusive will rectify both sides ofthe alternating current Wave.

While a single element is shown in both constructions it is evident A.that the number of elements may be increased depending on the resistance thereof and the desired voltage and 'the elements may have 'any desired construction as for instance a single straight wiremaybe'used although I prefer to use a coil so as to increase the potential drop per unit length of the coil.

Many modifications of the invention maybe resorted to without departing from the spirit thereof, and I donot therefore desire to limit myself to what has been shown and described except as such limitations occur inthe appended claims.

What I desire to claim is:

1. In a rectifier for alternating Vcurrent in a 'load-containing circuit a resistance wire, a

vcoating of electron emitting material upon the surface of said wire containing alkaline earth Ymetal oxides, an electrode positioned in the vicinity of said wire, and an ionizable gas having a pressure of substantially 200mm. `of

mercury surrounding said element and electrode, the breakdown potential of said gas when ionized by the emission of electrons from the coating of electron material arising from the passage of a current through the resistance wire being less per unit length along said wire than the unit potential necessary to bring said Wire and coating to electron emitting temperature.

2. In a rectifier for alternating current in aload-containing circuit, a coil of resistance Wire, a coating of electron emitting material upon the surface of said coil, an electrode positioned in the vicinity of said coil, and a mixtureof neon and argon gas surrounding said coil and electrode Y and having a pressure of substantially 200 mm. of mercury.

SAMUEL RUBEN. 

